title: Optimal positive end-expiratory pressure during robot-assisted laparoscopic radical prostatectomy.
abstract: BACKGROUND
  Increased intra-abdominal pressure during laparoscopic surgery causes cephalad displacement of the diaphragm, resulting in the formation of atelectasis, which can be overcome by positive end-expiratory pressure (PEEP). The aim of this prospective study was to investigate the level of optimal PEEP to maintain adequate arterial oxygenation and hemodynamics during robot-assisted laparoscopic radical prostatectomy (RLRP).
  
  
  METHODS
  One hundred patients undergoing RLRP were randomly allocated to one of five groups (n = 20) (0, 3, 5, 7 and 10 cmH2O of PEEP). Hemodynamic variables and respiratory parameters were measured at baseline with the patient in the supine position; at 30 min, 1, 2, 3 and 4 h during CO2 insufflation with the patient in the post-Trendelenburg position; and after deflation in the supine position with increasing PEEP.
  
  
  RESULTS
  The PaO2 levels and alveolar-arterial difference in oxygen tension (AaDO2) were improved in patients with PEEPs compared with patients in whom PEEP was not used. The application of PEEP (10 cmH2O) resulted in higher PaO2 levels compared to those with lower PEEP levels, but excessive peak airway pressure (PAP) was sometimes observed. The application of a PEEP of 7 cmH2O resulted in similar PaO2 levels without causing excessive PAP. There was a significant difference in central venous pressure between the groups, but there were no significant differences in heart rate, mean arterial pressure or minute ventilation between the groups.
  
  
  CONCLUSIONS
  A PEEP of 7 cmH2O is associated with the greater improvement of PaO2 and AaDO2 without causing excessive PAP during RLRP.
authors.affiliation: Department of Anesthesiology and Pain Medicine, College of Medicien, Hanyang University, Seoul, Korea.
authors.forename: Hee Jong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Kyo Sang
authors.initials: KS
authors.lastname: Kim
authors.forename: Ji Seon
authors.initials: JS
authors.lastname: Jeong
authors.forename: Jae Chul
authors.initials: JC
authors.lastname: Shim
authors.forename: Eun Sun
authors.initials: ES
authors.lastname: Cho
keywords: Hemodynamics; Laparoscopy; Positive end-expiratory pressure; Prostatectomy; Robotics